Apparatus for treating molten metals, alloys, and steels.



L. M. V. H. BARADUG-MULLER.

APPARATUS FOR TREATING MOLTEN METALS, ALLOYS, AND STEELS. APPLICATIONFILED 141111.29, 1912.

1,077,925. Patented Nov. 4, 1913.

2 SHEBTS-SHEET 1.

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l W/Wmsfs j VE/VTOR', M4 i M m w 3 OLfZQ/CLH fl/ My L. M. V. H.BARADUO-MULLER. APPARATUS FOR TREATING MOLTEN METALS, ALLOYS, ANDSTEELS.

APPLICATION FILED MAR.29, 1912.

Patented Nov. 4, 1913.

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flm-w acid or basic furnace, acid or basic Bessemer UNITED STATES-OFFICE- LOUIS MARIE vrc'ron nirromzrn Balsamic-mourn, or rams, salmon;

arrana'rus ron rnna'rriie momma METALS, annoys, AND s'rnnns. 1

Specification of LettersIatent. 7

Original application filed August 16, 1911 Serial No. 644,884. Dividedand 1912. Serial-Ho. 687,009.

this application filed larch as,

To all whom it may concern Be it known that I, LOUIS MA InVm'rORHIPPOLYTE BAnAnUo-MULLnn, a cltlzen of the .epublic .of France, residingin Paris,-

France, have invented certain .new and useful Improvements in Apparatusfor Treating Molten Metals, Alloys, and Steels, of which the followingis a specification.

-The resent application is a division ofv my ap ication Serial No.644,384, filed August 16, 1911, and describes and claims an apparatusdescribed and claimed in said application- There are two sources of thegases which exist in metals andalloys and in particular cast steels. Oneofthese is the conditions under which the melting furnace (cruciblefurnace, acid or basic Siemens-Martin furnace) is operated, or theconditions under which the refining furnace (Siemens-Martin,

converter) is operated. The other source is the internal chemicalreactions which give rise to gases (for example the chemical reactionsof carbonaceous matter on the oxids fused or dissolved in the li uidmetal). -It is not possible to distingulsh sharply between these sourcesof gases since they exist concomitantly and vary only in theirrespective intensities. However this may be,-'for a given thermal andchemical treatment to maximum quantit;

which a given metal is subjected at a lven temperature in a given'melting dr r ing furnace there is produced an equilibrium between thequantities of gases derived from the first and second sourcesrespectively, an equilibrium which corresponds with the fused metal oral y and of which animportant port-ion remains in the cold solidifiedmetal.

The gases which are most generally found in cold metals, allo s andsteels after they have been subject .to i neous fusion, are hydrogen,nitrogen, car n-mon'oxid; and carbon-dioxid. It is logical to admit thatthese same gases existed in solution in the melted metals, alloysand'steels and that i only the total quantity, and the relation of eachto this total, vary, owing to the fact that the gases escape during thecooling. A study of the formation of these gases and an attempt torealize the condition in which they exist in metals generally show 65that they are simply dissolved and not in the of gas dissolved in theerated at this moment dissolve in form of stable chemical combinations.In fact the quantity of dissolved gases depends on the nature and thetemperature of the fused alloy, on the pressure and on the chemicalcomposition of the external gaseous atmosphere, in' such a mannerth'attity maybe represented by Q=Kf(MTP) inwhich K is a co-efiicientdependent on the' nature of the'metal, onthe composition A Patented l{ov. 4,1913.

the quan- I of the gases and on the surface of the metal I plains t efact that metals, alloys and steels melted in a blast crucible furnacecontain more gases than the same metal melted in a Y and that steel madein anacid or basic. converter contains more gas than steel of the samecomposition prepared an acid or basic Siemens-Mariam furnace. In fact inthe Bessemer converter orthe Thomas con verter the pr re 'of the blastexceeds-that of the atmosp ere by about 1.5 kilo, so-that there isgaseous supersaturation and superoxidation.

When at the finishing point the oxid produced is reduced by carboh, thegases genpart and increase the proportion o gases in solution in the hotmetal. When the liquid metals, alloys and steels cool, they con-. tract,and the pressure set up by the dimi; nution of the volume of the metalincreases, at each instant of the cooling, the

pressure of'the dissolved gases, until this pressure becomessufiiciently great to overcome the atmospheric pressure and theinternalfriction, Iwhich oppose the escape of the gases. From this moment thegases .escape regularlyinto the atmosphere untilthe internal friction,which increases rapidly. as solidification proceeds, prevents more andmore this escape, Finally the escapeof the gases becomes extremely slowor even imcrucible furnace operatedby natural draft eater possible. Thusthe state of equilibrium is attained for ordinary temperature and pres.

sure, and corresponds with a certain proporthe atmosphere. above themetal there areformed in the subjacent still liquid metal pocketswherein the'pressure of the gases may be very much higher than that ofthe atmosphere even when the ingot is cold.

' Finally a mechanical agitation, notably a gyratory movement, bycreating in a liquid metal a centrifugal force, engenders anaccumulation of the metal at the periphery and increases the pressure inthe metal. This pressure is transmitted to the dissolved gases andexpels them in. the form of bubbles which escapefprincipally at theperiphery of the moving metal. These phenomena prove the simpledissolution of the gases in the melted metals and the unstable state ofequilibrium in which they are until the metal has completely cooled, astate of equilibrium of dissolution which is only attained owing to theinfluence of atmospheric pressure which opposes all prematuredisengagement of the gases. It is logical therefore to admit that if onecould upset this equilibrium of dissolution by diminishing the externalpressure tangentially to the same of the alloy while this is stillliquid, it should be possible to extract from the melted alloy all thedissolved gases whatever may be their source. The prob- -lem isparticularly worthy of being solved in the case of steels produced inacid or basic converters for such steelsmay contain, even when they arecold 4, 5 or even 10 times their volume of gas according to theirchemical composition and the duration of the thermal treatment and thecooling operation to which they are subjected.

The present invention has for its object to provide an apparatus forremoving from metals, alloys and steels not only the gases which may bedisengaged by the cooling of the metal but those which remain actuallyoccluded in the cold ingots of metal, alloy or steel which haveundergone igneous fusion whatever may be the character of the meltingfurnace or refining furnace used. For this purpose the gases areextracted from the metal, alloy or steel while they are still liquid,that is to say under the best con-' ditions for facilitating thedisengagement of the gases, so that ingots or castings are obtalnedwhich are free from dissolved 0ccluded gases and therefore'have a veryhigh degree of compactness and homogeneity. In this manner blow holesand pockets which form in the head of the ingot and thus depreciate'thevalue of the head to gaseous materials designed for refining themetalsand giving them a desired composition have been added in the course ofthe metallurgical treatment. This removal of the gases from the liquidmetals is accomplished by producing in the apparatus above the surfaceof the liquid metal, alloy. or steel a vacuum substantially complete,for instance, a-vacuum represented by 1 mm. of

mercury or thereabout. Under this high vacuum the gases are extractedfrom the perfectly liquid metal, alloy or steel ata high temperature.

The gases contained in the melted steel or other metal are extractedunder a high vacuum produced by high power reciprocating or rotarypumps, water ejectors, steam or air 'ejectors, or other suitableapparatus of high power, and the withdrawn gases are energeticallychilled as soon as they are extracted from the liquid metal. Thisenergetic chilling of the gases extracted, before they arrive at theextracting apparatus, may be produced in different manners such as byatomizing them with steam or cold Water, by circulating them throughapparatus analogous to gas washers, or by passing them through-bundlesof tubes around which cold brine or other liquid or cold air, gases orvapors are circulated. It is essent al to insist on the special partwhich this chilling of the gases issuing from the liquid metals plays,because, owingto this the volume of the gases is very much reduced sothat the extracting apparatus can remove per unit time a much moreconsiderable weight of gas owing to the small volume of the gas.

The arrangement of the pumps may be varied according to circumstances.Thus they may be in series or in parallel and combinedlor not with waterpumps or ejectors.

A combination which gives very good results comprises the applicationfor the extraction of the gases of pumps, which in the first place lowerthe pressure to a value corresponding With the maximum useful effect ofthe pumps and then substituting automatically for these'pum-ps vacuumejectors operated by water or better by steam or compressed air, andadapted to produce finally a substantially absolute vacuum above theliquid met-a1, alloy or steel, the pressure being thus reduced to amillimeter of mercury or thereabout. 7

An embodiment of the invention isillustrated in the accompanyingdrawings, wherein-' a 7 Figurel illustrates a front elevation of theapparatus with parts in section. Fig. 2

shows a plan of the apparatus with parts in section. Figs. 3 and 4illustrate details of the apparatus. Fig. 5 illustrates diagrammaticallytwo sets of apparatus arranged to. work in co'tiperation. Fig. 6 is adiagram illustrating different positions of valves in certain stages ofthe working of the apparatus illustrated in Fig. 5.

Referring to the drawings, the apparatus comprises a vertical cylinder35 of sheet steel autogenously soldered, containing a bundle of tubes 36analogous to that of a tubular boiler. These tubes are surrounded. by acooling fluid which may enter at the top of the cylinder in 37 and leaveat the bottom thereof at 38 after having been more or less heated by thebundle of tubes.

The lower part of the cylinder 35 is surrounded by a collar or sleeve 39(see Fig. 3) made in several segments bolted together. This collar orsleeve is constricted to accommodate between itself and the lower partof the cylinder. a washer ring of rubber or other suitable material 40,for the purpose of making a tight joint. Against this washer ring may beapplied a circular flange 41 of the ladle 1 containing the liquid metalor steel which is to be deprived of gases. In order to hermeticallyclose the joint it suffices to mount the ladle 1 on a suitable press andforce the said circular flange 41 against the under surface of therubber washer; for instance the carriage 2 carrying the casting ladlemay be brought onto the platform of a hydraulic press 42 situated belowthe cylinder 35. As soon as the proper degree of pressure has beenapplied by the hydraulic press the vacuum pumps may be put in action.

The bottom of the cylinder 35 (see Figs. 1 and 3) is preferably inwardlycurved so as to form a sleeve of water 43 in contact with the rubberwasher 40, so as to prevent alterafixing= solder 49.

the liquid metal under action of the vacuum 1tiolrli of the joint byheat radiated'from the The lower tube plate 44 within the cylinder 35 issituated at such a height in the latter that there is left a spacebetween the surface of the melted metal and this plate sufficient toinsure that particles of melted metal 'which maybe ejected from the massby are cooled in the bundle of tubes so that their temperature fallsfrom say 14501500*to 350300 C.

For the purpose of more completely cooling the gases there may becombined with the cooler just described a second apparatus comprising acylinder 50 containing a bundle of tubes 51. Cooling fluid, such aschilled brine, is admitted into the bottom part of this cylinder by 5:2and leaves the latter at the upper part at 53. The two cylinders 35 and50 are connected at the top by a suitable pipe 54 so that the gaseswhich are cooled in the first cylinder descend in the second through thetubes 51 which are chilled by the circulating fluid and issue from thissecond cylinder at its lower part where the pipe 55 communicates withthe vacuum pumps. This second apparatus may lower the temperature of thegases to-15 C. or less. The gases then enter the vacuum pumps and theejectors.

When the extraction of the gases from the molten metal is finished,which is known by the constancy of the vacuum as indicated by a gage,air is admitted into the cylinder 35 above thecasting ladle little bylittle, either by opening the cylinder directly to the atmosphere or,which is better, connecting it with a second evacuating apparatusmounted in series with the .first so that the vacuum in the one cylindermay serve to evacuate partially the other, so as to diminish the Work ofthe vacuum pumps in extracting gas from the second evacuating apparatus.When atmospheric pressure isfinally reestablished in the apparatus thehydraulic platfrom 42 is lowered and the casting ladle 1 which nowcontains a charge of liquid metal free from gas is conducted to theingot molds.

I The construction of the apparatus arranged to work in series is showndiagrammatically in Fig. 5. Two sets of apparatus are shown as workingtogether. Two threeway cocks are placed one in each of the pipes 54, 54connecting the vacuum cylinders 35, 35 with the auxiliary coolingcylinders 50, 50. These three-way cocks are connected by a pipe 60.

(1) When it is desired to begin the exhaustion of gases from the metalof ladle 1, the cooks R R are turned to the position 1) Fig. 6. In thisposition the two vacuum cylinders 35, 35 are placed in communication andthe pressures therein can equalize.

The cocks R R are then turned to the pofrom the metal 'of'ladle 1 hasbeen completed and it is desired to begin the removal of the gases fromthe metal in ladle 1, the cocks R and R are turned to the position (3Fig-6. This places the rarefied vacuum chamber 35 in communication withthe vac uum cylinder 35 in which the evacuation has not yet begun,and-there results an equalization of pressures, the vacuum in cylinder35 being partially reduced and a partial vacuum being produced incylinder 35. The cocks are then turned to the position (4.) Fig. 6, inwhich position the cylinder 35 is cut oil from the cylinder-35 andconnected with its evacuating pumps andejectors through the pipe 55. Theladle 1 is then removed from its vacuum cylinder.

What I claim is 1. Apparatus for removing gasesfrom steel and the like,comprising in combination a vertical vacuum chamber having an openbottom, a removable receptacle for the molten-metal adapted tomakeanair-tight joint with the .bottom of said vacuum chamber,

means for pressing said receptacle'upwardly againstihe under side ofsaid vacuum chamber, means for evacuating said vacuum chamber, and meansfor :rapidly and extensively cooling the air and gases evacuated fromsaid chamber prior to reaching said evacuating means.

2. Apparatus for removing gases from steel and thelike, comprisingincombination a vertical vacuum chamber, a receptacle for the molten metaladapted to make an airtight joint with the bottom-of said vacuumchamber, means for evacuating said vacuum chamber, and means for rapidlyand extensively cooling the air and gases evacuated from said chamberprior to reaching said evacuating means, said means having a capacitv ofcooling said air and gases to a temperature of approximately 0 C.

3. Apparatus for removing gases from steel and the like, comprising incombination a vertical vacuum chamber having an open bottom, areceptacle for the molten metal adapted to make an air-tight joint withthe.

bottom of said vacuum chamber, means for pressing said receptacleupwardly against the under side of said vacuum chamber, .means forevacuating-said vacuum chamber, and means for rapidly and extensivelycooling the air and gases evacuated from said chamber prior to reachingsaidevacuating means, said means comprising a cylinder having tubestherein for the passage of gases and adapted to contain a cooling fluidaround said tubes.

4. Apparatus for removing gases from steel-and the like, comprising incombination a vertical vacuum chamber having an open bottom, a removablereceptacle for the molten metal adapted to make an air-tight joint withthebottom of said vacuum chamber,

means for pressing said receptacle upwardly against the under side :ofsaid vacuum cham ber, means for evacuating said vacuum chamber, meansfor rapidly and extensively cooling the air and .gases evacuated fromsaid chamber prior to reaching said evacuating means, said meanscomprising a compartment in the upper part of said vacuum chamberadapted to contain a cooling fluid, and tubes passingthrough saidcompartment through whichwthe air and gases to be cooled are adapted topass.

5. Apparatus for removing gases from steel and the like, comprisingincombination a vertical vacuum chamber, a removable receptacle for themolten :metal adapted to make an air-tight joint withzthe bottom of.

said vacuum chamber, means for evacuating said vacuum chamber,said'vacuum chamber having a plastic -.Washer-ring at its lower end andmeans Tfor cooling said washer-ring and-said receptacle having acircular flange adapted to fit against said washer, and means forrapidly and extensively cooling the air andgases evacuated from saidchamber priorto reachingsaid evacuating means.

-6. Apparatus for removing gases from steel and-the like, comp-rising incombination a vertical vaeuumchamber, a receptacle for the molten metaladapted to make an airtight joint with the bottom of said vacuumchamber, and means for evacuating said vacuum chamber,said vacuumchamber having a water jacket at its lower end to prevent the heat fromsaid'molten metal-receptacle affecting the joint between said receptacleand chamber.

7. Apparatus for removing gases from steel and the like, comprising incombination a vertical vacuum chamber, a receptacle for the molten metaladapted to :make an air- -tight joint with the bottom of said vacuumchamber, means for evacuating said Vacuum chamber, means for rapidly andextensively cooling the air and gases evacuated from said chamber priorto reaching said evacuati-ng means, said means comprising a compartmentin.=the'upperpart of said vacuum chamber adapted to contain a coolingfluid, andtubes passing through said compartment through which the airandgases to be cooled are adapted to pass, and asecond cooling apparatusoutside of said vacuum" chamber comprising a tubular cylinder havingpipes therein for the passage of the air and gases surrounded by acooling medium.

8. Apparatus for :removing gases from steel and-the like, comprising incombination a vertical vacuum chamber, a receptacle for the molten metaladapted to make an airtight joint with the bottom of said vacuumchamber, and means for evacuating said 'vacuum chamber, said receptaclehaving a :tap-hole-therein, arefractory plug for closin-g-said-tap hole,and a metal cap outside of said plug adapted to seal said tap-holeagainst the entrance of air and adapted to be pierced by the moltenmetal after the refractory-plug is withdrawn.

9. Apparatus for removing gases from stceland the like, comprising incombinationtwo Vertical vacuum fchambers, two receptacles for moltenmeta-l'ada-pted .to make airtight joints WltlllllB bottoms of saidvacuum chambers, and means for evacuating said vacuum chamber, saidvacuum chambers being adapted to be placed in communication with oneanother whereby air in one-chameration is completedtherein.

her, before the beginning of the evacuating operation therein, may beevacuated into said other chamber after the evacuating op- In' Witnesswhereof, I have hereunto signed my name 1n the presence of twosubscribing witnesses.

LOUIS MARIE VICTOR HIPPOLYTE BARADUC-MULLER.

\Vitnesses LUCIEN MEMMINGER, CHARLES MARDELET.

